Using '===' is enough to perform check if it's the same object really quickly. It actually compares only object ID's

The problem is actualy in a really HUGE data structure passed to the logger.

While tracing it includes Upper level of PHPUnit objects + all ZF test case objects including their properties (additional objects using during testing)!
It's large enough structure even Zend_Log_Writer_FirebugTest test case is started separately (takes ~25sec), but it becomes too large if whole ZF tests suite is started.

I'm going to mark testAdvancedLogging(Zend_Log_Writer_FirebugTest) as skipped since it passes without problems in a separate mode.